This invention relates to novel spirosuccinimide derivatives, to the processes for their preparation, to methods for using the compounds, and to pharmaceutical preparations thereof. The compounds have pharmaceutical properties which render them beneficial for the treatment of diabetes mellitus and associated conditions.
For many years diabetes mellitus has been treated with two established types of drugs, namely insulin and oral hypoglycemic agents. These drugs have benefited hundreds of thousands of diabetics by improving their well-being and prolonging their lives. However, the resulting longevity of diabetic patients has led to complications such as neuropathy, nephropathy, retinopathy, cataracts and atherosclerosis. These complications have been linked to the undesirable accumulation of sorbitol in diabetic tissue, which in turn resulted from the high levels of glucose characteristic of the diabetic patient.
In mammals, including humans, the key enzyme involved in the conversion of hexoses to polyols (e.g. the sorbitol pathway) is aldose reductase. J. H. Kinoshita and collaborators, see J. H. Kinoshita et al, Biochem, Biophys. Acta, 158,472 (1968) and references cited therein, have demonstrated that aldose reductase plays a central role in the etiology of galactosemic cataracts by effecting the conversion of galactose to dulcitol (galactitol) and that an agent capable of inhibiting aldos reductase can prevent the detrimental accumulation of dulcitol in the lens. Furthermore, a relationship between elevated levels of glucose and an undesireable accumulation of sorbitol has been demonstrated in the lens, peripheral nerves and kidney of diabetic animals, see A. Pirie and R. van Heyningen, Exp. Eye Res., 3,124 (1964); L. T. Chylack and J. H. Kinoshita, Invest. Ophthal., 8,401 (1969) and J. D. Ward and R. W. R. Baker, Diabetol., 6,531 (1970).
The closest prior art is D.R. Brittain, European Patent 168181 (1985) and D. R. Brittain et al, European Patent 65407 (1982). D. R. Brittain et al disclose spirosuccinimide-indolinone derivatives having aldose reductase activity. Still other related compounds having similar activity are spirosuccinimide derivatives of T. Irikura, et al, European Patent 147805 (1984) and C. A. Lipinsik, European Patent 136143, (1984). The compounds of the present invention differ in that they are members of novel ring systems. Accordingly, the present compounds represent an important new approach for treatment of diabetes mellitus.
Non-insulin dependent diabetes mellitus (Type II diabetes) is usually treated by a regimen including diet, exercise, oral agents such as sulfonylureas and, in more severe cases, insulin. Many of these hypoglycemic agents exhibit severe side effects. This, along with their generally limited efficacy, has created a need for new, novel and more potent antidiabetic agents which do not possess these drawbacks.
Ciglitazone [(.+-.)-5-[4-[(1-methylcyclohexyl)methoxy]benzyl]-thiazolidine-2,4-dione] is currently considered one of the most unique and promising drugs for treatment of hyperglycemia and hyperinsulinemia [Fujita et al, Diabetes, 32, 804 (1983)] because it normalizes these parameters. K. Megura et al, European Patent 208420 (1986), K. Megura et al, European Patent 193256 (1985), disclose other thiazolinine-dione containing compounds having antihyperglycemic activity useful for treating diabetes. The compounds of the present invention also possess antihyperglycemic activity and are of novel structure. Accordingly, the present compounds represent an important new approach for the treatment of diabetes mellitus.